CERCLE CHROMATIQUE (GRATUIT) Fxphd - visual effects and production training. CGTalk. Specular. Specular Properties Specular computes the same simple (Lambertian) lighting as Diffuse, plus a viewer dependent specular highlight. This is called the Blinn-Phong lighting model. It has a specular highlight that is dependent on surface angle, light angle, and viewing angle. The highlight is actually just a realtime-suitable way to simulate blurred reflection of the light source. Additionally, the alpha channel of the main texture acts as a Specular Map (sometimes called "gloss map"), defining which areas of the object are more reflective than others. Performance Generally, this shader is moderately expensive to render.